Re: Patch to disarm timers after an exec syscall

[Andrew Morton <akpm@osdl.org>]

Gernot Payer <gpayer@suse.de> wrote:
>
> while running the openposix testsuite I saw testcase timer_create/9-1.c 
>  failing. This testcase tests whether timers are disarmed when a process calls 
>  exec, as described in e.g. 
>  http://www.opengroup.org/onlinepubs/009695399/functions/timer_create.html.
> 
>  The attached one-liner patch (+ one line comment) fixes this issue. I did the 
>  diff against 2.6.12.1, but the fix is pretty much the same for every other 
>  2.6.x kernel I had a look at.
> 
>  I don't think this patch breaks anything, as relying on this (undocumented) 
>  behaviour would imho be bad style.
> 
>  So tell me what you think, and if you have some pointers to interesting 
>  discussions about Linux and POSIX compliance then I would like to read that 
>  as well.
> 
>  --- linux-2.6.12.1-orig/fs/exec.c	2005-06-29 14:29:31.069738264 +0200
>  +++ linux-2.6.12.1/fs/exec.c	2005-06-29 14:34:46.034856288 +0200
>  @@ -1200,6 +1200,10 @@
>   		acct_update_integrals(current);
>   		update_mem_hiwater(current);
>   		kfree(bprm);
>  +
>  +		/* delete old itimers */
>  +		exit_itimers(current->signal);
>  +		
>   		return retval;
>   	}

Ouch.  What does 2.4.x do?

It wouldn't surprise me if fixing this breaks _something_ out there.  We
might have to remain non-POSIX-compliant for the rest of time.